NO. 8 INSECT ABDOMEN — SNODGRASS 'J'J 



it is seen, however, that the fold bearing the gonopore is a part of 

 the eighth sternum, there is then no discrepancy between the Blattidae 

 and other Orthoptera, either with regard to the position of the gono- 

 pore or that of the spermathecal opening. 



Any doubt that the sclerite (or group of sclerites) on the fold 

 bearing the female gonopore in the Blattidae represents the true 

 eighth sternum is dispelled by observing the muscle connections with 

 the seventh sternum and the eighth tergum. Ford (1923) says con- 

 vincingly " the sclerite is clearly eighth sternal ", because her statement 

 is based on the fact that the sternal muscles from the seventh segment 

 are inserted on its anterior margin, and that tergosternal muscles of 

 the eighth segment are attached upon it laterally. Hence, the female 

 gonopore of adult Blattidae has the same morphological position as 

 in other adult Orthoptera. It is probable that the female gonopore 

 originates in the Blattidae on the posterior part of the seventh venter 

 behind the seventh sternum, as it is known to do in various other 

 insects, and that the position of the definitive opening is secondary. 

 A migration of the gonopore in the roaches, however, has not been 

 observed. Nel's (1930) statement that the median oviduct of Blattella 

 originates on the seventh intersegmental membrane is based on his 

 view that this membrane forms the fold bearing the gonopore, which 

 is here interpreted as the eighth sternum. The female gonopore of 

 adult Blattidae has the usual location on the posterior part of the 

 eighth segment, and is not situated either on the seventh segment, or 

 between the seventh and eighth sterna. 



The ovipositor of Blatta is reduced and its parts are of irregular 

 form as in other members of the Blattidae, but it retains all the ele- 

 ments of a typical orthopteroid ovipositor, including two pairs of 

 valvifers and three pairs of valvulae. 



The first, or ventral, valvulae (fig. 24 C, iVl) are widely divergent 

 proximally, where they are connected with a pair of small basal plates 

 (iVlf). These basal sclerites, though separated by a considerable 

 space from the eighth sternum, are clearly the first valvifers since 

 upon them are inserted muscles from the tergum of the eighth seg- 

 ment, and because they are directly continuous with the ventral val- 

 vulae. Each valvifer, however, is fused with an irregular sclerite (e) 

 behind it, which belongs to the ninth segment, as shown by the fact 

 that it lies posterior to the intersegmental groove (g) and is continuous 

 with the ninth tergum {I XT) by a slender sclerotic strip on the pos- 

 terior margin of the fold. This sclerite (e) Crampton (1925, 1929) 

 calls the " valvifer ", but it is not the homologue of the sclerite he 

 terms " valvifer " in Gryllidae and Tettigoniidae ; it is evidently the 



